The combination of kidney function variables with cell cycle arrest biomarkers identifies distinct subphenotypes of sepsis-associated acute kidney injury: a post-hoc analysis (the PHENAKI study).

BACKGROUND: The severity and course of sepsis-associated acute kidney injury (SA-AKI) are correlated with the mortality rate. Early detection of SA-AKI subphenotypes might facilitate the rapid provision of individualized care. PATIENTS AND METHODS: In this post-hoc analysis of a multicenter prospective study, we combined conventional kidney function variables with serial measurements of urine (tissue inhibitor of metalloproteinase-2 [TIMP-2])* (insulin-like growth factor-binding protein [IGFBP7]) at 0, 6, 12, and 24 h) and then using an unsupervised hierarchical clustering of principal components (HCPC) approach to identify different phenotypes of SA-AKI. We then compared the subphenotypes with regard to a composite outcome of in-hospital death or the initiation of renal replacement therapy (RRT). RESULTS: We included 184 patients presenting SA-AKI within 6 h of the initiation of catecholamines. Three distinct subphenotypes were identified: subphenotype A (99 patients) was characterized by a normal urine output (UO), a low SCr and a low [TIMP-2]*[IGFBP7] level; subphenotype B (74 patients) was characterized by existing chronic kidney disease (CKD), a higher SCr, a low UO, and an intermediate [TIMP-2]*[IGFBP7] level; and subphenotype C was characterized by very low UO, a very high [TIMP-2]*[IGFBP7] level, and an intermediate SCr level. With subphenotype A as the reference, the adjusted hazard ratio (aHR) [95%CI] for the composite outcome was 3.77 [1.92-7.42] (p < 0.001) for subphenotype B and 4.80 [1.67-13.82] (p = 0.004) for subphenotype C. CONCLUSIONS: Combining conventional kidney function variables with urine measurements of [TIMP-2]*[IGFBP7] might help to identify distinct SA-AKI subphenotypes with different short-term courses and survival rates.

Automated vs. conventional ventilation in the ICU: a randomized controlled crossover trial comparing blood oxygen saturation during daily nursing procedures (I-NURSING).

BACKGROUND: Hypoxia is common during daily nursing procedures (DNPs) routinely performed on mechanically ventilated patients. The impact of automated ventilation on the incidence and severity of blood oxygen desaturation during DNPs remains unknown. METHODS: A prospective randomized controlled crossover trial was carried out in a French intensive care unit to compare blood oxygen pulse saturation (SpO2) during DNPs performed on patients mechanically ventilated in automated and conventional ventilation modes (AV and CV, respectively). All patients with FiO2 ≤ 60% and without prone positioning or neuromuscular blocking agents were included. Patients underwent two DNPs on the same day using AV (INTELLiVENT-ASV®) and CV (volume control, biphasic positive airway pressure, or pressure support ventilation) in a randomized order. The primary outcome was the percentage of time spent with SpO2 in the acceptable range of 90-95% during the DNP. RESULTS: Of the 265 included patients, 93% had been admitted for a medical pathology, the majority for acute respiratory failure (52%). There was no difference between the two periods in terms of DNP duration, sedation requirements, or ventilation parameters, but patients had more spontaneous breaths and lower peak airway pressures during the AV period (p <  0.001). The percentage of time spent with SpO2 in the acceptable range during DNPs was longer in the AV period than in the CV period (48 ± 37 vs. 43 ± 37, percentage of DNP period; p = 0.03). After adjustment, AV was associated with a higher number of DNPs carried out with SpO2 in the acceptable range (odds ratio, 1.82; 95% CI, 1.28 to 2.6; p = 0.001) and a lower incidence of blood oxygen desaturation ≤ 85% (adjusted odds ratio, 0.50; 95% CI, 0.30 to 0.85; p = 0.01). CONCLUSION: AV appears to reduce the incidence and severity of blood oxygen desaturation during daily nursing procedures (DNPs) in comparison to CV. TRIAL REGISTRATION: This study was registered in clinical-trial.gov ( NCT03176329 ) in June 2017.

Hepatocyte spheroids as a viable in vitro model for recapitulation of complex in vivo metabolism pathways of loratadine in humans.

Accurate prediction of in vivo metabolic pathways in humans can be challenging because in vitro liver matrices may fail to produce certain in vivo metabolites.Rat and human spheroids, generated from cryopreserved hepatocytes in media that contained minimal amount of serum, maintained morphology, viability and cytochrome P450 (CYP) activities for at least a week without media exchange.With spheroid cultures, multiple Phase I and Phase II metabolites were observed in rat and human spheroid cultures that were incubated with loratadine (LOR) for multiple days. Consistent with in vivo observations, 3-hydroxydesloratadine, (3-OH-DL), along with its glucuronide, were observed in human spheroids, but not in rat spheroids. Interestingly, the putative intermediate metabolite leading to 3-OH-DL, DL-N-glucuronide, was observed in incubations with both rat and human spheroids. In conclusion, hepatocyte spheroid were capable of recapitulating the inter-species differences in metabolism between human and rat for LOR, therefore, it may represent a viable model for studying complex metabolic pathways.

Angiostrongylus cantonensis Is an Important Cause of Eosinophilic Meningitis in Southern Vietnam.

We utilized polymerase chain reaction (PCR) to demonstrate that Angiostrongylus cantonensis was responsible for 67.3% of 55 cases of eosinophilic meningitis from a cohort of 1,690 adult patients with CNS infection at a tertiary hospital in southern Vietnam. Longer duration of illness, depressed consciousness, and peripheral blood eosinophilia were associated with PCR positivity.

The synthesis of [14 C]4-acetylphenylalanine, effect on cell viability, and assessment of protein incorporation in male rat hepatocytes.

PEGylation is a proven approach to prolonging the duration of action and enhancing biophysical solubility and stability of peptides. 4-Acetylphenylalanine is a novel amino acid with a ketone side chain that is uniquely reactive in proteins. The ketone functionality can react with an aminooxy functionalized polyethyleneglycol polymer to form a stable oxime adduct of the protein. One concern with using unnatural amino acids, such as 4-acetylphenylalanine, is the possibility of it being cleaved from the peptide and becoming incorporated into endogenous proteins. To determine whether this occurs, an in vitro experiment to assess the cell viability and amino acid incorporation into endogenous proteins using primary male rat hepatocytes in the presence of [14 C]4-acetylphenylalanine, 4 or [14 C(U)]L-phenylalanine was conducted. [14 C]4-acetylphenylalanine, 4 was prepared in 2 radiochemical steps from [1-14 C]acetyl chloride in an overall 8% radiochemical yield and in 99.9% radiochemical purity. The results showed that there was no evidence of carbon-14 incorporation into hepatocyte endogenous proteins with [14 C]pAcF and there was no difference between it and L-phenylalanine in cell viability assessments at any of the concentrations studied between 0.1 and 1000 µM.

Early intravenous high-dose vitamin C in postcardiac arrest shock (VICEPAC): study protocol for a randomised, single-blind, open-label, multicentre, controlled trial.

INTRODUCTION: The high incidence of morbidity and mortality associated with the post-cardiac arrest (CA) period highlights the need for novel therapeutic interventions to improve the outcome of out-of-hospital cardiac arrest (OHCA) patients admitted to the intensive care unit (ICU). The aim of this study is to assess the ability of high-dose intravenous vitamin C (Vit-C) to improve post-CA shock. METHODS AND ANALYSIS: This is a single-blind, open-label, multicentre, randomised controlled trial, involving 234 OHCA patients with post-CA shock planned to be enrolled in 10 French ICUs. Patients will be randomised to receive standard-of-care (SOC) or SOC with early high-dose intravenous Vit-C administration (200 mg/kg per day, within 6 hours after return of spontaneous circulation, for 3 days). The primary endpoint is the cumulative incidence of vasopressor withdrawal at 72 hours after enrolment, with death considered as a competing event. The main secondary endpoints are neurological outcome, mortality due to refractory shock, vasopressor-free days and organ failure monitored by the sequential organ failure assessment score. ETHICS AND DISSEMINATION: The study protocol was approved by a French Ethics Committee (EC) on 21 February 2023 (Comité de Protection des Personnes Ile de France 1, Paris, France). Due to the short enrolment period to avoid any delay in treatment, the EC approved the study inclusion before informed consent was obtained. As soon as possible, patient and their relative will be asked for their deferred informed consent. The data from the study will be disseminated through conference presentations and peer-reviewed publications. TRIAL REGISTRATION NUMBER: NCT05817851.

Protocol for fever control using external cooling in mechanically ventilated patients with septic shock: SEPSISCOOL II randomised controlled trial.

INTRODUCTION: Fever treatment is commonly applied in patients with sepsis but its impact on survival remains undetermined. Patients with respiratory and haemodynamic failure are at the highest risk for not tolerating the metabolic cost of fever. However, fever can help to control infection. Treating fever with paracetamol has been shown to be less effective than cooling. In the SEPSISCOOL pilot study, active fever control by external cooling improved organ failure recovery and early survival. The main objective of this confirmatory trial is to assess whether fever control at normothermia can improve the evolution of organ failure and mortality at day 60 of febrile patients with septic shock. This study will compare two strategies within the first 48 hours of septic shock: treatment of fever with cooling or no treatment of fever. METHODS AND ANALYSIS: SEPSISCOOL II is a pragmatic, investigator-initiated, adaptive, multicentre, open-label, randomised controlled, superiority trial in patients admitted to the intensive care unit with febrile septic shock. After stratification based on the acute respiratory distress syndrome status, patients will be randomised between two arms: (1) cooling and (2) no cooling. The primary endpoint is mortality at day 60 after randomisation. The secondary endpoints include the evolution of organ failure, early mortality and tolerance. The target sample size is 820 patients. ETHICS AND DISSEMINATION: The study is funded by the French health ministry and was approved by the ethics committee CPP Nord Ouest II (Amiens, France). The results will be submitted for publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT04494074.

Sox, Fox, and Lmx1b binding sites differentially regulate a Gdf5-Associated regulatory region during elbow development.

Introduction: The articulating ends of limb bones have precise morphology and asymmetry that ensures proper joint function. Growth differentiation factor 5 (Gdf5) is a secreted morphogen involved in cartilage and bone development that contributes to the architecture of developing joints. Dysregulation of Gdf5 results in joint dysmorphogenesis often leading to progressive joint degeneration or osteoarthritis (OA). The transcription factors and cis-regulatory modules (CRMs) that regulate Gdf5 expression are not well characterized. We previously identified a Gdf5-associated regulatory region (GARR) that contains predicted binding sites for Lmx1b, Osr2, Fox, and the Sox transcription factors. These transcription factors are recognized factors involved in joint morphogenesis and skeletal development. Methods: We used in situ hybridization to Gdf5, Col2A1, and the transcription factors of interest in developing chicken limbs to determine potential overlap in expression. We further analyzed scRNA-seq data derived from limbs and knees in published mouse and chicken datasets, identifying cells with coexpression of Gdf5 and the transcription factors of interest. We also performed site-directed mutatgenesis of the predicted transcription factor binding sites in a GARR-reporter construct and determined any change in activity using targeted regional electroporation (TREP) in micromass and embryonic chicken wing bioassays. Results: Gdf5 expression overlapped the expression of these transcription factors during joint development both by in situ hybridization (ISH) and scRNA-seq analyses. Within the GARR CRM, mutation of two binding sites common to Fox and Sox transcripstion factors reduced enhancer activity to background levels in micromass cultures and in ovo embryonic chicken wing bioassays, whereas mutation of two Sox-only binding sites caused a significant increase in activity. These results indicate that the Fox/Sox binding sites are required for activity, while the Sox-only sites are involved in repression of activity. Mutation of Lmx1b binding sites in GARR caused an overall reduction in enhancer activity in vitro and a dorsal reduction in ovo. Despite a recognized role for Osr2 in joint development, disruption of the predicted Osr2 site did not alter GARR activity. Conclusion: Taken together, our data indicates that GARR integrates positive, repressive, and asymmetrical inputs to fine-tune the expression of Gdf5 during elbow joint development.

NMR-based metabolomics of mammalian cell and tissue cultures.

NMR spectroscopy was used to evaluate growth media and the cellular metabolome in two systems of interest to biomedical research. The first of these was a Chinese hamster ovary cell line engineered to express a recombinant protein. Here, NMR spectroscopy and a quantum mechanical total line shape analysis were utilized to quantify 30 metabolites such as amino acids, Krebs cycle intermediates, activated sugars, cofactors, and others in both media and cell extracts. The impact of bioreactor scale and addition of anti-apoptotic agents to the media on the extracellular and intracellular metabolome indicated changes in metabolic pathways of energy utilization. These results shed light into culture parameters that can be manipulated to optimize growth and protein production. Second, metabolomic analysis was performed on the superfusion media in a common model used for drug metabolism and toxicology studies, in vitro liver slices. In this study, it is demonstrated that two of the 48 standard media components, choline and histidine are depleted at a faster rate than many other nutrients. Augmenting the starting media with extra choline and histidine improves the long-term liver slice viability as measured by higher tissues levels of lactate dehydrogenase (LDH), glutathione and ATP, as well as lower LDH levels in the media at time points out to 94 h after initiation of incubation. In both models, media components and cellular metabolites are measured over time and correlated with currently accepted endpoint measures.

Apixaban Pharmacokinetics and Pharmacodynamics in Subjects with Mild or Moderate Hepatic Impairment.

BACKGROUND: Hepatic impairment can impact apixaban pharmacokinetics and pharmacodynamics by decreasing cytochrome P450-mediated metabolism and factor X production. OBJECTIVE: This study evaluated the effect of mild or moderate (Child-Pugh A and B) hepatic impairment on apixaban pharmacokinetics, pharmacodynamics, and safety. METHODS: This open-label, parallel-group, single-dose study included eight mildly and eight moderately hepatically impaired subjects, and 16 healthy subjects. Subjects received a single oral apixaban 5-mg dose (day 1). Pharmacokinetic, pharmacodynamic, and safety assessments were completed at prespecified time points. Apixaban maximum plasma concentration and area under the concentration-time curve to infinity were compared between subjects with hepatic impairment and healthy subjects. RESULTS: Apixaban area under the concentration-time curve to infinity point estimates and 90% confidence intervals were 1.03 (0.80-1.32) and 1.09 (0.85-1.41) for subjects with mild and moderate hepatic impairment vs healthy subjects. Maximum plasma concentration results were similar. Mean (standard deviation) apixaban unbound fraction was 6.8% (1.4), 7.9% (1.8), and 7.1% (1.3) in subjects with mild or moderate hepatic impairment and in healthy subjects. Mean change from baseline in international normalized ratio (3 h post-dose) was 14.7%, 12.7%, and 10.7% for subjects with mild or moderate hepatic impairment and healthy subjects, respectively. A direct relationship was observed between apixaban anti-factor Xa activity and plasma concentration across groups. No serious adverse events or discontinuations due to adverse events occurred. CONCLUSIONS: Mild or moderate hepatic impairment had no clinically relevant impact on apixaban pharmacokinetic or pharmacodynamic measures, suggesting that dose adjustment may not be required.

Hemiboeachanii (Gesneriaceae), a new species from limestone areas of northern Vietnam.

Hemiboeachanii, a new species of Gesneriaceae from Ha Giang Province, northern Vietnam, is here described and illustrated. It has many branched stems, diamond-shaped involucre with two cirrose opposite apices, a pink corolla, red spotted inside, and a flowering time in January-February. Among congeners with an externally hairy corolla, this new species is morphologically close to H.crystallina and H.sinovietnamica. Diagnostic discriminative characters in all mentioned species are discussed. The conservation status of this species is considered to be "Critically endangered" (CR) according to the IUCN Red List Categories and Criteria.

Sustained low-efficiency dialysis with regional citrate anticoagulation for patients with liver impairment in intensive care unit: A single-center experience.

Regional citrate anticoagulation (RCA) is a recommended method for extracorporeal circuit anticoagulation during renal replacement therapy (RRT). Increased risk of citrate accumulation by default of hepatic metabolism limits its use in liver failure patients. A Catot /Caion ratio ≥2.5 is established as an indirect control of plasma citrate poisoning. To investigate the safety of RCA in patients with liver impairment during sustained low-efficiency dialysis (SLED), we conducted a retrospective study of 41 patients with acute or chronic hepatocellular failure requiring RRT between January 2014 and June 2015 in the intensive care unit of the Groupe Hospitalier Sud Ile de France. Sixty-seven SLED sessions were performed. At admission, 32 (78%) patients had acute liver dysfunction and nine (22%) patients had cirrhosis with a median MELD score of 27 (IQR: 18.8, 42.0). Despite a majority of poor prognosis patients (SAPS-II (Simplified Acute Physiology Score II) score 71 [IQR: 58; 87]), with acute liver impairment as a part of multi-organ failure, no dosage of Catot /Caion ratio after SLED sessions exceeded the critical threshold of 2.5. Of the 63 complete sessions, neither dyscalcemia nor major dysnatremia, nor extracorporeal circuit thrombosis were noticed. Observed acid-base disturbances (16.4%) were not significantly correlated with the Catot /Caion ratio (P = .2155). In this retrospective study using RCA during intermittent RRT in ICU patients with severe liver dysfunction, we did not observe any citrate accumulation but monitoring of acid-base status and electrolytes remains necessary to ensure technique safety.

Dexamethasone in Vietnamese adolescents and adults with bacterial meningitis.

BACKGROUND: It is uncertain whether all adults with bacterial meningitis benefit from treatment with adjunctive dexamethasone. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of dexamethasone in 435 patients over the age of 14 years who had suspected bacterial meningitis. The goal was to determine whether dexamethasone reduced the risk of death at 1 month and the risk of death or disability at 6 months. RESULTS: A total of 217 patients were assigned to the dexamethasone group, and 218 to the placebo group. Bacterial meningitis was confirmed in 300 patients (69.0%), probable meningitis was diagnosed in 123 patients (28.3%), and an alternative diagnosis was made in 12 patients (2.8%). An intention-to-treat analysis of all the patients showed that dexamethasone was not associated with a significant reduction in the risk of death at 1 month (relative risk, 0.79; 95% confidence interval [CI], 0.45 to 1.39) or the risk of death or disability at 6 months (odds ratio, 0.74; 95% CI, 0.47 to 1.17). In patients with confirmed bacterial meningitis, however, there was a significant reduction in the risk of death at 1 month (relative risk, 0.43; 95% CI, 0.20 to 0.94) and in the risk of death or disability at 6 months (odds ratio, 0.56; 95% CI, 0.32 to 0.98). These effects were not found in patients with probable bacterial meningitis. Results of multivariate analysis indicated that dexamethasone treatment for patients with probable bacterial meningitis was significantly associated with an increased risk of death at 1 month, an observation that may be explained by cases of tuberculous meningitis in the treatment group. CONCLUSIONS: Dexamethasone does not improve the outcome in all adolescents and adults with suspected bacterial meningitis; a beneficial effect appears to be confined to patients with microbiologically proven disease, including those who have received prior treatment with antibiotics. (Current Controlled Trials number, ISRCTN42986828 [controlled-trials.com] .).

Duration of prone position sessions: a prospective cohort study.

BACKGROUND: Prone position (PP) is highly recommended in moderate-to-severe ARDS. However, the optimal duration of PP sessions remains unclear. We searched to evaluate the time required to obtain the maximum physiological effect, and to search for parameters related to patient survival in PP. METHODS AND RESULTS: It was a prospective, monocentric, physiological study. We included in the study all prone-positioned patients in our ICU between June 2016 and January 2018. Pulmonary mechanics, data from volumetric capnography and arterial blood gas were recorded before prone positioning, 2 h after proning, before return to a supine position (SP) and 2 h after return to SP. Dynamic parameters were recorded before proning and every 30 min during the session until 24 h. 103 patients (ARDS 95%) were included performing 231 PP sessions with a mean length of 21.5 ± 5 h per session. They presented a significant increase in pH, static compliance and PaO2/FiO2 with a significant decrease in PaCO2, Pplat, phase 3 slope of the volumetric capnography, PetCO2, VD/VT-phy and ΔP. The beneficial physiological effects continued after 16 h of PP and at least up to 24 h in some patients. The evolution of the respiratory parameters during the first session and also during the pooled sessions did not find any predictor of response to PP, whether before, during or 2 h after the return in SP. CONCLUSIONS: PP sessions should be prolonged at least 24 h and be extended in the event that the PaO2/FiO2 ratio at 24 h remains below 150, especially since no criteria can predict which patient will benefit or not from it. Trial registration The trial has been registered on 28 June 2016 in ClinicalTrials.gov (NCT02816190) (https://clinicaltrials.gov/ct2/show/NCT02816190?term=propocap&rank=1).

Immunological and biochemical correlates of adjunctive dexamethasone in Vietnamese adults with bacterial meningitis.

Adjunctive treatment to improve outcome from bacterial meningitis has centered on dexamethasone. Among Vietnamese patients with bacterial meningitis, cerebrospinal fluid (CSF) opening pressure and CSF:plasma glucose ratios were significantly improved and levels of CSF cytokines interleukin (IL)-6, IL-8, and IL-10 and were all statistically significantly lower after treatment in patients who were randomized to dexamethasone, compared with levels in patients who received placebo.

CYP3A4-mediated ester cleavage as the major metabolic pathway of the oral taxane 3'-tert-butyl-3'-N-tert-butyloxycarbonyl-4-deacetyl-3'-dephenyl-3'-N-debenzoyl-4-O-methoxycarbonyl-paclitaxel (BMS-275183).

3'-tert-Butyl-3'-N-tert-butyloxycarbonyl-4-deacetyl-3'-dephenyl-3'-N-debenzoyl-4-O-methoxycarbonyl-paclitaxel (BMS-275183) is an orally available taxane analog that has the potential to be used as an oral agent to treat cancers. The compound is similar to the two clinically intravenously administered taxanes, paclitaxel and docetaxel, in that it contains a baccatin ring linked to a side chain through an ester bond. Unlike the other taxanes, the hydrolysis of this ester bond leads to formation of a free baccatin core (M13) that was the major metabolism pathway in incubations of [(14)C]BMS-275183 in human liver microsomes (HLMs) in the presence of NADPH, but it was not formed in incubations with human liver cytosol or HLM in the absence of NADPH. The other prominent metabolites formed in HLM incubations resulted from oxidation of t-butyl groups on the side chain (M20, M20B, M21, M22, and M23). All these metabolites were formed by cDNA-expressed CYP3A and not by other cytochrome P450 (P450) enzymes tested. Formation of these metabolites was selectively inhibited by ketoconazole and troleandomycin. The formation of M13 followed Michaelis-Menten kinetics with the K(m) values of 1.3 to 2.4 muM in HLM or CYP3A4; the V(max) value for the formation of M13 and M23 in the cDNA-expressed CYP3A4 matched well (within 2-fold difference) with that determined in HLM when expressed in units of per picomole of P450. These results showed that BMS-275183 is metabolized by CYP3A4 to yield baccatin through oxidation of side-chain t-butyl groups. An intramolecular cyclization of a side-chain hydroxylation metabolite is proposed to be responsible for the formation of M13, the side-chain hydrolysis metabolite.

Metabolism and excretion of an oral taxane analog, [14C]3'-tert-butyl-3'-N-tert-butyloxycarbonyl-4-deacetyl-3'-dephenyl-3'-N-debenzoyl-4-O-methoxy-paclitaxel (BMS-275183), in rats and dogs.

3'-tert-Butyl-3'-N-tert-butyloxycarbonyl-4-deacetyl-3'-dephenyl-3'-N-debenzoyl-4-O-methoxy-paclitaxel (BMS-275183) is a taxane analog that has the potential for oral use in the treatment of various types of cancer. In this study, the metabolism and excretion of [(14)C]BMS-275183 were evaluated after a single oral administration of [(14)C]BMS-275183 to rats and dogs (15 and 1 mg/kg, respectively). To aid metabolite identification by mass spectrometry (MS), a stable labeled (phenyl-(13)C(6)) BMS-275183 was included in 1:1 ratio of (13)C(6)/(12)C in the dose administration. Fecal excretion was the major route of elimination for [(14)C]BMS-275183 in both species (85-86 and <9% of the dose in feces and urine, respectively). The highest radioactivity in plasma was observed at 1 h postdose, suggesting rapid absorption of the drug in both species. The total radioactivity in plasma was measurable up to 24 h postdose. Metabolites were identified by liquid chromatography-MS and/or NMR spectroscopy. [(14)C]BMS-275183 was the prominent component in rat and dog plasma and was detected up to 24 h along with various oxidative and hydrolytic metabolites. [(14)C]BMS-275183 was extensively metabolized in both species, forming mainly oxidative metabolites, and unchanged parent drug accounted for <3.5% of the administered dose in urine and feces. The prominent metabolites resulted from oxidation of the tert-butyl groups on the side chain and further oxidation and cyclization of the tert-butylhydroxylated metabolites. A total of 30 oxidative metabolites including M13, a prominent ester cleavage metabolite, were identified in rat and dog samples.

The effect of ketoconazole on the pharmacokinetics and pharmacodynamics of ixabepilone: a first in class epothilone B analogue in late-phase clinical development.

PURPOSE: To determine if ixabepilone is a substrate for cytochrome P450 3A4 (CYP3A4) and if its metabolism by this cytochrome is clinically important, we did a clinical drug interaction study in humans using ketoconazole as an inhibitor of CYP3A4. EXPERIMENTAL DESIGN: Human microsomes were used to determine the cytochrome P450 enzyme(s) involved in the metabolism of ixabepilone. Computational docking (CYP3A4) studies were done for epothilone B and ixabepilone. A follow-up clinical study was done in patients with cancer to determine if 400 mg/d ketoconazole (inhibitor of CYP3A4) altered the pharmacokinetics, drug-target interactions, and pharmacodynamics of ixabepilone. RESULTS: Molecular modeling and human microsomal studies predicted ixabepilone to be a good substrate for CYP3A4. In patients, ketoconazole coadministration resulted in a maximum ixabepilone dose administration to 25 mg/m(2) when compared with single-agent therapy of 40 mg/m(2). Coadministration of ketoconazole with ixabepilone resulted in a 79% increase in AUC(0-infinity). The relationship of microtubule bundle formation in peripheral blood mononuclear cells to plasma ixabepilone concentration was well described by the Hill equation. Microtubule bundle formation in peripheral blood mononuclear cells correlated with neutropenia. CONCLUSIONS: Ixabepilone is a good CYP3A4 substrate in vitro; however, in humans, it is likely to be cleared by multiple mechanisms. Furthermore, our results provide evidence that there is a direct relationship between ixabepilone pharmacokinetics, neutrophil counts, and microtubule bundle formation in PBMCs. Strong inhibitors of CYP3A4 should be used cautiously in the context of ixabepilone dosing.

Nanopillared Surfaces Disrupt Pseudomonas aeruginosa Mechanoresponsive Upstream Motility.

Pseudomonas aeruginosa is an opportunistic, multidrug-resistant, human pathogen that forms biofilms in environments with fluid flow, such as the lungs of cystic fibrosis patients, industrial pipelines, and medical devices. P. aeruginosa twitches upstream on surfaces by the cyclic extension and retraction of its mechanoresponsive type IV pili motility appendages. The prevention of upstream motility, host invasion, and infectious biofilm formation in fluid flow systems remains an unmet challenge. Here, we describe the design and application of scalable nanopillared surface structures fabricated using nanoimprint lithography that reduce upstream motility and colonization by P. aeruginosa. We used flow channels to induce shear stress typically found in catheter tubes and microscopy analysis to investigate the impact of nanopillared surfaces with different packing fractions on upstream motility trajectory, displacement, velocity, and surface attachment. We found that densely packed, subcellular nanopillared surfaces, with pillar periodicities ranging from 200 to 600 nm and widths ranging from 70 to 215 nm, inhibit the mechanoresponsive upstream motility and surface attachment. This bacteria-nanostructured surface interface effect allows us to tailor surfaces with specific nanopillared geometries for disrupting cell motility and attachment in fluid flow systems.

Biomimetic Nanopillared Surfaces Inhibit Drug Resistant Filamentous Fungal Growth.

Filamentous fungi are invasive and multidrug resistant pathogens that commonly contaminate biomedical devices and implants. Once spherical fungal spores attach to a surface, they exhibit germ tube development, hyphal growth, and robust biofilm formation. Nanotopography found on plants, reptiles, and insect wings possess bactericidal properties during prokaryotic cell adhesion. Here, we demonstrate the application of biomimetic nanopillars that inhibit eukaryotic filamentous fungal growth and possess fungicidal properties. Furthermore, many spores on the nanopillars appeared deflated, while those on the flat surfaces remained spherical and intact. These antifungal phenomena provide promising applications in antifouling biointerfaces for biomedical devices and implants.